When printing with certain types of printers, such as ink jet printers, the type of media can have an effect on print quality. For example, while minimum ink migration may occur when printing on glossy photographic paper, a higher degree of migration will occur when printing on plain paper. Optimizing print on different color media may require different ink mixing. For this reason, many printers control ink volumes and other print characteristics based on media type.
Various media recognition mechanisms have been utilized. For example, many printers allow a user to indicate media type. Based on the media type information provided by the user, the printer can vary print characteristics.
Alternatively, an automated media detection system can be used. For example, a media detect sensor can be used to read an invisible-ink code pre-printed on the media.
Another type of automated media detection system uses a transmitter and two receptors at differing angles with respect to the surface of the media. The two sensors are used to measure, respectively, the specular reflectance of the media and the diffuse reflectance of the media. The ratio of these two reflectance values are analyzed to identify specific media type. Alternatively, a Fourier transform of the to reflective values is used to generate a spatial frequency signature for media. See, for example, U.S. Pat. No. 6,561,643 B1 issued to Walker et al. for Advanced Media Determination System for Inkjet Printing.